When mounting a tire on a wheel, the tire is usually seated in a rim. The rim can either be endless, or divided, namely consist of a plurality, for example three segmental rim parts.
Where endless rims are used, a tire may not be safely mounted on the rim. The disadvantage of endless rims, however, is the fact that the tire cannot be easily assembled and disassembled from the rim, and special tools or machinery is needed to mount a tire on an endless rim, or once mounted, to remove the tire from the rim.
Another type of rim consists of a plurality, for example three segmental rim parts. While it is easy to mount a tire on segmental rim parts, and once mounted, to install the tire rim assembly on the wheel body.
A rim using a plurality of segmental rim parts is disclosed, for example in U.S. Pat. No. 2,062,722 issued to Mijnssen, assigned to the instant assignee, based on Swiss Pat. No. 175,208.
Mijnssen teaches that the inner circumference of the rim is provided laterally of the middle plane thereof with a beveled seating face which rests against a matching, conical seating face on the heads of the spokes or arms of a spider-shaped wheel body. The heads of the spokes carry bolts provided with clips which, on one hand, bear against their respective head, and, on the other hand against the front side of a seating projection providing at its blunt end the seating faces of the rim. As shown, for example, in FIG. 1 of the above-noted Mijnssen patent, segmental rim parts 5,6, and 7 are clearly seen in FIG. 1. If a tire is mounted on a rim consisting of such a plurality of rim parts, 5, 6, & 7, and air is pumped into the tire, the pressure of the tire causes the rim parts to abut one another so as to substantially close the gaps 8 shown in FIG. 1. When an air-inflated tire is mounted on the rim, the resulting change in the diameter of the rim due to compression by the force of the tire is at least partially cancelled by a radially outward pressure being exerted on the rim. The resulting pressure may result, however, in the rim being expanded too much. To prevent such undue expansion, the wheel body for segmental rim parts of this type is provided with stop-means or clamping-means, which largely prevent the segmental rim parts from becoming unintentionally loose from the wheel body.
While the afore-mentioned Mijnssen uses a nut and bolt arrangement and a plurality of clips to secure the wheel body to the rim, British Pat. No. 346,913 based on Swiss Pat. No. 144,737, also assigned to the instant assignee, uses an endless holding or clamping ring provided with a plurality of holes, and including at least one annular laterally extending projection to mate with a corresponding groove in the segmental rim parts. A plurality of bolts 15 are threaded into the wheel body 13, and once in place in the wheel body 13, receive the ring 14, the bolt 15 projecting through corresponding holes in the ring 14. Finally nuts are threaded onto the bolts, so as to clamp the ring 14 to the wheel body 13 and to the rim 1.
It will be seen that the trend in the views is to provide lateral stop means, so that when the nuts, threaded onto respective bolts 15, are tightened the lateral extension 19 abuts a corresponding flat portion of an annular groove, in, for example the rim 1. In several embodiments, in addition to the ring 14 being provided with a lateral extension, the wheel body 13 is also provided with a lateral extension, for example extension 21 shown in FIG. 5, both lateral extensions embracing a radially inward projection of the rim 1 to insure that the rim 1 is clamped between the ring 14 and the wheel body 13. In the embodiment shown in FIG. 4, where only a single laterally facing annular extension 19 is provided on the ring 14, it will be observed that a clearance exists between the extension 19 and the rim 1. Thus when the nut is tightened on the bolt 15, in the event the rim 1 slides laterally leftwards from the facing 11, the effect of the clearance in the groove of the rim 1 is to avoid stressing the relatively weak ring 14. The holding mechanism therefore secures the rim segments in a radial direction to guard against an emergency, for instance when a tire bursts (page 2, lines 19-21).
Commercial applications of the prior art are of the type TUBLEX.RTM. for endless rims, are of the type UNILEX.RTM. where a plurality of rim parts are used, and are of the construction TRILEX.RTM. where specifically only three segmental rim parts are used.
The construction of the afore-described prior art are such that the last-named construction TRILEX.RTM. is relatively safe, however this type of rim has no counterpart for wheel bodies of the U.S.-28.degree. type.